In the drilling of exploratory wells such as oil wells, rigs are employed which can be transported to a site and assembled in place to perform the drilling operation. It is necessary to provide elevated drill floors to provide a space thereunder for equipment, such as, for example, safety devices and blowout preventers. The drilling rig must have a base suitable to support the rig on infirm soil so that the weight of the rig and the drilling equipment supported on the floor will be distributed over the base for transfer to the surface of the earth.
Previously developed elevating structures have included the system described in U.S. Pat. No. 4,135,340 issued to Cox et al on Jan. 23, 1979 and entitled "Modular Drill Rig Erection Systems". However, such systems have involved difficult loading and pin connections.
The need exists for an elevatable floor structure in a drill rig which allows for all pin connections to be made at ground level upon raising of the floor. Relative ease and efficient installation and erection of a high level drill floor as it supports the tower portion of the drilling rig are highly desirable. Additionally, a need has arisen for a drilling rig wherein floor substructure can readily be installed with the necessary level of stability.